/*
 * Copyright (C) 2005-2011 MaNGOS <http://www.getmangos.com/>
 *
 * Copyright (C) 2008-2011 Trinity <http://www.trinitycore.org/>
 *
 * Copyright (C) 2010-2011 ProjectSkyfire <http://www.projectskyfire.org/>
 * 
 * Copyright (C) 2011 ArkCORE <http://www.arkania.net/>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef _VMAPTOOLS_H
#define _VMAPTOOLS_H

#include <G3D/CollisionDetection.h>
#include <G3D/AABox.h>

#include "NodeValueAccess.h"

/**
 The Class is mainly taken from G3D/AABSPTree.h but modified to be able to use our internal data structure.
 This is an iterator that helps us analysing the BSP-Trees.
 The collision detection is modified to return true, if we are inside an object.
 */

namespace VMAP {
template<class TValue>
class IntersectionCallBack {
public:
	TValue* closestEntity;
	G3D::Vector3 hitLocation;
	G3D::Vector3 hitNormal;

	void operator()(const G3D::Ray& ray, const TValue* entity,
			bool pStopAtFirstHit, float& distance) {
		entity->intersect(ray, distance, pStopAtFirstHit, hitLocation,
				hitNormal);
	}
};

//==============================================================
//==============================================================
//==============================================================

class MyCollisionDetection {
private:
public:

	static bool collisionLocationForMovingPointFixedAABox(
			const G3D::Vector3& origin, const G3D::Vector3& dir,
			const G3D::AABox& box, G3D::Vector3& location, bool& Inside) {
		// Integer representation of a floating-point value.
#define IR(x)   (reinterpret_cast<G3D::uint32 const&>(x))

		Inside = true;
		const G3D::Vector3& MinB = box.low();
		const G3D::Vector3& MaxB = box.high();
		G3D::Vector3 MaxT(-1.0f, -1.0f, -1.0f);

		// Find candidate planes.
		for (int i = 0; i < 3; ++i) {
			if (origin[i] < MinB[i]) {
				location[i] = MinB[i];
				Inside = false;

				// Calculate T distances to candidate planes
				if (IR(dir[i])) {
					MaxT[i] = (MinB[i] - origin[i]) / dir[i];
				}
			} else if (origin[i] > MaxB[i]) {
				location[i] = MaxB[i];
				Inside = false;

				// Calculate T distances to candidate planes
				if (IR(dir[i])) {
					MaxT[i] = (MaxB[i] - origin[i]) / dir[i];
				}
			}
		}

		if (Inside) {
			// definite hit
			location = origin;
			return true;
		}

		// Get largest of the maxT's for final choice of intersection
		int WhichPlane = 0;
		if (MaxT[1] > MaxT[WhichPlane]) {
			WhichPlane = 1;
		}

		if (MaxT[2] > MaxT[WhichPlane]) {
			WhichPlane = 2;
		}

		// Check final candidate actually inside box
		if (IR(MaxT[WhichPlane]) & 0x80000000) {
			// Miss the box
			return false;
		}

		for (int i = 0; i < 3; ++i) {
			if (i != WhichPlane) {
				location[i] = origin[i] + MaxT[WhichPlane] * dir[i];
				if ((location[i] < MinB[i]) || (location[i] > MaxB[i])) {
					// On this plane we're outside the box extents, so
					// we miss the box
					return false;
				}
			}
		}
		/*
		 // Choose the normal to be the plane normal facing into the ray
		 normal = G3D::Vector3::zero();
		 normal[WhichPlane] = (dir[WhichPlane] > 0) ? -1.0 : 1.0;
		 */
		return true;

#undef IR
	}
};
}
#endif
